Drug delivery devices for setting and dispensing a single or multiple doses of a liquid medicament are as such well-known in the art. Generally, such devices have substantially a similar purpose as that of an ordinary syringe.
Drug delivery devices, in particular pen-type injectors have to meet a number of user-specific requirements. For instance, with patient's suffering chronic diseases, such like diabetes, the patient may be physically infirm and may also have impaired vision. Suitable drug delivery devices especially intended for home medication therefore need to be robust in construction and should be easy to use. Furthermore, manipulation and general handling of the device and its components should be intelligible and easy understandable. Moreover, a dose setting as well as a dose dispensing procedure must be easy to operate and has to be unambiguous.
Typically, such devices comprise a housing or a particular cartridge holder, adapted to receive a cartridge at least partially filled with the medicament to be dispensed. The device further comprises a drive mechanism, usually having a displaceable piston rod, which is adapted to operably engage with a piston of the cartridge. By means of the drive mechanism and its piston rod, the piston of the cartridge is displaceable in a distal or dispensing direction and may therefore expel a predefined amount of the medicament via a piercing assembly, which is to be releasably coupled with a distal end section of the housing of the drug delivery device.
The medicament to be dispensed by the drug delivery device is provided and contained in a multi-dose cartridge. Such cartridges typically comprise a vitreous barrel sealed in distal direction by means of a pierceable seal and being further sealed in proximal direction by the piston. With reusable drug delivery devices an empty cartridge is replaceable by a new one. In order to provide access to an empty cartridge the housing of the drug delivery device has to be opened or disassembled. One approach to replace an empty cartridge by a new one is to make use of a housing comprising at least two mutually detachable components, e.g. a body and a cartridge holder. Typically, the body serves to accommodate the drive mechanism comprising all those mechanically interacting components of the drug delivery device that are necessary to displace a piston rod in a distal, hence in a dispensing direction, in order to expel a medicament from the cartridge. A second housing component releasably interconnectable with the body typically serves as a cartridge holder. The cartridge holder is designed to receive and to accommodate the cartridge filled with the medicament to be dispensed.
Typically, the cartridge holder features at least one transparent inspection window allowing to visually inspect the filling level of the cartridge. Moreover, the distal end of such a cartridge holder is typically equipped with a standardized connector to releasably engage with a piercing assembly, e.g. a double-tipped needle. By attaching or engaging the piercing assembly with the cartridge holder, a proximally extending needle portion may extend through a distal opening of the cartridge holder so as to penetrate and to pierce a seal located at a distal end of the cartridge. By attaching the needle assembly to the cartridge holder a fluid transferring access to the interior of the cartridge can be established.
Cartridge holder and body can be releasably connected in many different ways. Document EP 2 121 086 B1 discloses a medical delivery system comprising a locking ring with L-shaped grooves. This medical delivery system comprises a container and a dosing assembly adapted to be fastened to the container, wherein one of the dosing assembly and the container defines a first part having at least one projection which during fastening of the container to the dosing assembly is adapted to be received in or by at least one corresponding groove or projection of a second part which is defined by the other one of the dosing assembly and the container. There, the first part comprises a fixed part and a rotatable element defining at least one of said projection and/or groove, which during fastening of the container to the dosing assembly is adapted to be received in or by at least one of said corresponding groove and/or projection of the second part.
Certain aspects of the disclosure can be implemented to provide a smooth operating, long lasting and intuitively operable connector assembly for releasably connecting a proximal body and a distal cartridge holder of a drug delivery device's housing. The connector assembly should feature a minimum of mechanically interacting components. It should be intuitive and easy in handling and should further allow and support an easy, cost efficient and straightforward assembly during a manufacturing process of the drug delivery device.